Direct-writing recording elements yielding silver and dye images



United States Patent 3,508,922 DIRECT-WRITING RECORDING ELEMENTS YIELDING SILVER AND DYE IMAGES Eugene Dwight Seiter, Westfield, N.J., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware No Drawing. Filed Mar. 22, 1967, Ser. No. 624,983

Int. Cl. G03c N76 US. Cl. 96-68 12 Claims ABSTRACT OF THE DISCLOSURE Os'cillograph recording elements comprising a support, e.g., film or paper, a direct-writing, light-developable, blue-sensitive silver halide layer having an extra range of sensitivity in the green and/ or red regions of the spectrum, and a direct-writing, light-developable, blue-sensitive silver halide layer, at least one of said layers containing a nondiffusing color former.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to direct-writing or printing, lightdevelopable oscillographic recording elements, e.g., films or papers that can be used to produce silver-containing images by light-development and to produce colored images by color coupling development.

Description of the prior art At the present time photographic oscillographic recording papers developable to a black trace image by photolysis are known and disclosed in Hunt US. Patent 3,033,678 3,033,682, Bigelow US. Patent 3,178,293 and in US. applications Ser. No. 588,734 filed Oct. 24, 1966, now abandoned and Ser. No. 519,436 filed Jan. 10, 1966. It is also known to prepare two color photographic papers for recording oscillographic traces in color that require chemical processing However, prior to this invention, photorecording oscillographic papers were not known which after exposure in an oscillograph or similar instrument could not only be light-developed to a black trace image, but could be processed chemically to provide colored trace images. Oscillographic trace images in various colors have considerable utility. This is because traces indicating a variety of information may be superimposed partly or wholly. The prior art two-color paper which can record traces and be chemically processed to two diiferent colors only partially fills the requirement for versatility. Such papers that have been processed chemically only did not allow quick access to data recorded by photolysis.

SUMMARY OF THE INVENTION The elements of this invention comprise a support, a direct-writing, light-developable, blue-sensitive silver halide layer having an extra range of sensitivity in the green and/or red regions of the spectrum, and a directwriting, light-developable, blue-sensitive silver halide layer, at least one of said layers containing a non-diffusing color former.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The oscillographic photorecording elements of this invention when exposed to oscillographic traces or similar data-producing radiations can be developed to silver images by light development or photolysis or to colored images by chromogenic development and comprise a support bearing 3,508,922 Patented Apr. 28, 1970 blue-sensitive said layers containing silver halide grains having average grain size in the range O.110.0 microns dispersed in a water-permeable organic macromolecular colloid having protective colloid properties, each of said layers containmg -(A) A halogen acceptor in addition to any sensitizing dye which may also have a halogen accepting function. Suitable halogen acceptors include stannous salts such as stannous chloride, salts providing iodide and thiocyanate ions, molecular iodine, alkali metal nitrites; hydroquinones, e.g., hydroquinone, chlorohydroquinone and t-butylhydroquinone. 3-pyrazo-lidones such as 1-phenyl-3- pyrazolidone; phenyldiamines; aminophenols; amines and amine salts; compounds with an alkaline reaction, e.g., borax, alkali metal hydroxides and ammonium hydroxide; thiourea and substituted thiourea compounds described in US. Patent 3,287,136, Nov. 22, 1966; aromatic mercaptans, e.g., thiosalicylic acid, and other known halogen acceptors listed in the patents referred to; which halogen acceptors can be used with plumbous or copper salts; and

(B) At least one color former capable of forming a quinone-imine dye or another type dye upon colorcoupling development with the oxidation products of a primary aromatic amine color developing agent.

Various sensitizing dyes, e.g., merocyanine dyes and carbocyanine dyes, can be used in layer (1). Suitable specific such dyes are listed in US. Patent 3,287,136. Generally about 5 to 500 mg. or more of dye per mole of silver halide is adequate.

In a more preferred embodiment of the invention, each of the direct-Writing silver halide emulsion layers (1) and (2) as defined above contain, based on each mole of silver halide (a) 0.1 to 300 mole percent of cuprous thiocyanate, preferably 0.5 to 40 mole percent, or

(b) 0.5 to 15 mole percent and preferably 0.8 to 10 mole percent of an iodide ion-yielding compound, and 0.1 to mole percent of a water-soluble thiocyanate salt, and optionally (c) 0 to 120 mole percent of a Water-soluble bromide,

and

(d) 0 to 25 mole percent of a water-Soluble plumbous salt; at least one of said layers containing:

(e) at least on color former capable of forming a quinone-imine dye upon color-coupling development with the oxidation products of a primary aromatic amine color developing agent.

The emulsions can be made as described in the aboveidentified Hunt and Bigelow patents and in assignees U.S. applications Ser. No. 519,436 filed Jan. 10, 1966, Ser. No. 588,734 filed Oct. 24, 1966, now abandoned. In general they are made by precipitating the silver halides in the presence of a plumbous salt, digesting the resulting emulsions and either prior to, during or after digestion adding thereto either cuprous thiocyanate in an amount of 0.5 to 40 mole percent based on the silver halide or potassium iodide and a water-soluble thiocyanate. Before coating, sensitizers including optical sensitizing dyes are added where desired. In addition, the appropriate color formers, as indicated above, are added before coating. When exposed to oscillographic trace radiations and then to the photolyzing radiation of ordinary room light, a black trace image is formed on the material. When exposed through the appropriate filters and chemically 3 processed, color discriminating traces are obtained. Color formers other than magenta and cyan may be used. Also, there may be mixed with the magenta color former a yellow color former to increase color discrimination.

Preferably the photorecording element comprises at least two emulsion layers of the type described above containing a cyan color former in a mole ratio of silver halide (AgX) to dye of 3-12 AgX/l dye in an inner layer and a magenta color former in the ratio of 3-19 AgX/l dye in an outer layer. Exposure to orange-yellow light, followed by chemical processing will yield a cyan dye, while blue light will yield a magenta dye with chemical processing. White light exposure will yield both cyan and magenta dyes which together appear blue with chemical processing. With white light exposure and photolysis or light-development by ordinary room lighting a black (silver) image is obtained.

The photographic silver halide emulsions preferably are the silver bromide or silver chlorobromide type, but other types, i.e., chloride, iodobromide, etc. can be used. Suitable silver halides are those described in Hunt, U.S. Patents 3,033,678 and 3,033,682. The background density, image density, and image stability of such emulsion coatings depend on the silver halide combination employed and where necessary can be improved by the use of plurnbous salts and soluble bromide as taught by Hunt, U.S. Patent 3,033,682. The background density, image density, and image stability of such emulsion coatings depend on the silver halide combination employed and where necessary can be improved by the use of plumbous salts and soluble bromide as taught by Hunt, U.S. Patent 3,033,682. A particularly suitable system is that prepared by the method of Bigelow, U.S. Patent 3,178,293 in which the aqueous silver nitrate used in precipitating the silver halide contains a water-soluble plumbous salt.

After precipitating and ripening, the emulsion may or may not be, but preferably is, washed. Washing may be done as described in Moede, U.S. Patent 2,772,165. The emulsion is redispersed and digested in a conventional manner. At this point or prior to digestion, optical sensitizing dyes and chemical sensitizers, e.g., gold and sulfur sensitizers, are added as desired to increase the spectral response and over-all sensitivity of the emulsion for use in instruments employing a variety of light sources. Chemical sensitizers are particularly eflicacious in increasing the speed of chemically processed material. During or after this operation, cuprous thiocyanate and water soluble thiocyanate salt are added to the silver halide emulsion. Three alternate techniques which may be used are as follows:

(1) by adding a gelatino-cu-prous thiocyanate dispersion and a soluble thiocyanate salt to the emulsion. The gelatin dispersion may be prepared as described in Example I of Assignees Sincius, application U.S. Ser. No. 563,035 filed July 6, 1966';

(2) by adding cuprous thiocyanate dissolved as a complex salt in a concentrated aqueous solution of a soluble thiocyanate;

(3) by an in situ reaction in the silver halide emulsion between thiocyanate, bisulfite and Cu (II) ions.

After the digestion step, the appropriate color formers usual coating adjuvants, e.g., hardeners, wetting agents, etc. are added and the viscosity is adjusted as desired by the addition of a further amount of gelatin or other colloid. In general the ratio of gelatin to silver halide is 1:1; however, this is not at all critical. Many color formers appropriate for the purpose of providing dyes giving good color discrimination are known and references for suitable ones are listed below. The preferred color formers are those that are non-diffusing or nonmigratory and yield quinoneimine or azomethine dyes. Particularly useful are the polymeric color formers described in assignees Firestine et al. U.S. Patent 3,163,625

and assignees Umberger U.S. Patent 3,299,013, issued Jan. 17, 1967. The polymeric color formers are incorporated in an amount to provide about 407 equivalent weight of the cyan and about 633 for the magenta color formers. Equivalent weight is defined as the number of grams of polymer containing one mole of the color forming nucleus.

The prepared emulsions are then coated on a suitable support, e.g., paper, and dried to give a dry coating weight equivalent to about 30 mg. AgBr/dmP.

To determine the sensitometric characteristics of the material, it may be exposed through a 2l-step /2 wedge in an electronic flash sensitometer as described in US. Patent 3,033,678. This instrument uses a Xenon discharge tube and provides exposure times of 10- l0 10- 10 and 10 seconds. Relative sensitivities can be expressed as the relative number of steps recorded in the image. The exposed material may be light-developed by irradiation with room light or with a fluorescent black light tube, e.g., at about meter-candles intensity to form the black line trace images. The images became easily visible in from 1 to 300 seconds. To determine the densities of image and background, a reflection densitometer may be used whose values correspond to visual density. To test the stability of the background, the light-developed image is exposed for 15 hours to room light at about 50 meter-candles intensity. Speed in oscillography is measured in inches per second and is called writing speed. The usual radiation source is an oscillographic Osram high pressure arc lamp as described in U.S. Patent 3,033,678. Writing speeds are determined from frequency of the signal and the peakto-peak amplitude of oscillation as recorded on the paper. A typical oscillographic instrument generally has several galvanometers each directing a light source as a light trace corresponding to the signal. Where it is desired to record colored traces, the appropriate filters are installed so that the colors which strike each emulsion layer can be carefully controlled, this being well understood in the photographic art.

The invention will be further illustrated in and by the following examples but is not intended to be limited thereby.

EXAMPLE I A gelatino-silver chlorobromide emulsion was made by slowly adding an aqueous solution containing a mixture of 1 mole of silver nitrate and 0.033 mole of plumbous nitrate to a gelatin solution containing 1 mole of potassium chloride acidified with 0.05 mole of hydrochloric acid. The precipitation was carried out under a red safe-light. The temperature at precipitation and for 40 minutes thereafter was held at 160 F. After precipitation, an aqueous solution of 1.6 moles of potassium bromide was added while the mixture was held for 40 minutes at 160 F. The resulting emulsion was coagulated, washed and redispersed in accordance with the technique described in Moede, U.S. Patent 2,772,165. To the redispersed emulsion, there were added an xacarbocyanine sensitizing dye (to spectrally sensitize the emulsion to the green region of the spectrum) and gold and sulfur sensitizers. The resulting emulsion was digested at 150 F. for 40 minutes. To the digested emulsion, there was added, per 1.5 moles of silver halide the following:

Ml. Aqueous ammonium thiocyanate (10%) 91 Aqueous sodium bisulfite (1%) 500 0.1 M cupric nitrate (31-1 0) 120 the mixture was stirred for 5 minutes at F. This procedure yielded a silver halide/cuprous thiocyanate ratio of /l, or 0.8 mole percent cuprous thiocyanate with 8 mole percent thiocyanate present. To the resulting emulsion, there was added in addition to the usual harden- 1 (EH2 CH2 f I lTIH I C=O O where X +1.5X equals the number of units to give an equivalent weight of 407.

The cyan color former was made up and dispersed in the emulsion as described in Example V of assignees, Chu and Umberger, U.S. Ser. No. 447,573 filed Apr. 12, 1965. The emulsion was then coated on a paper support to give a dry coating weight equivalent to 23 mg. of silver bromide per square decimeter. The coated emulsion was dried in a conventional manner. Another emulsion was made as described above but was not optically sensitized and was digested at 140 F. for 40 minutes. The color former was a copolymeric magenta color former of the formula:

where X+3X equals the number of units to give an equivalent weight of 633. This color former was added in the manner described in Example V of the above Chu and Umberger Application in an amount to provide a ratio of silver halide to color former of /1. This emulsion was coated over the cyan color former containing emulsion to provide a dry coating weight equivalent of 21 mg. of silver bromide per square decimeter. The coated emulsion was dried in a conventional manner.

A sample of the resulting two-layer material was exposed in a Honeywell 1612 Oscillograph instrument using an Osram super high pressure mercury arc lamp Type HBO 107/1. The paper was transported through the machine at 8 inches per second where frequencies were 100 and 6000 cycles per second and amplitudes were to 1% inches. Writing speeds were approximately 200 to 13,000 inches per second. Traces were recorded with unfiltered radiation and with radiation through Wratten No. 12 yellow and Wratten No. 34 blue filters. The exposed material was light developed by exposing to room light of about 75 meter-candles intensity and an image became visible in approximately 60 seconds. The resulting exposed material was developed by photolysis yielding black traces or by immersing in a developing bath of the following composition:

4-amino-N-ethyl-N-(fi-methanesulfonamido ethy l)-m- 'toluidene sesquisulfate monohydrate-l0.0 grams l-phenyl-3pyrazolidone.125 gram 6-nitrobenzimidazole nitrate (1% in 1% NaOH sol.)--

Sodium sulfite (anhydrous)4.0 grams Sodium hydroxide 1 N-80.0 ml.

Sodium bromide-0.8 gram Sodium carbonate (anhydrous)30.0 grams Hydroxylamine hydrochloridel.0 gram Benzyl alcohol-12.0 ml.

1,3-diaminopropanol-2-5.0 grams Polyethylene oxide (a commercial grade of average molecular weight 30003700)-8.0 grams Water to make1.0 liter pH at 100 F., 11.0:01

The material was then immersed for 15 seconds in a stop bath comprising a 20% aqueous solution of sodium bisulfite. The element was then immersed in a bleach bath having the following composition:

Sodium bromide-30.0 grams Sodium sulfate-45.0 grams Potassium ferricyanide-123.0 grams Water to make1.0 liter pH at F., 8.0-8.6

The element was then immersed in a fixing solution having the following composition:

Sodium thiosulfate (anhydrous)153.0 grams Sodium sulfite (anhydrous)15.0 grams Sodium borate (borax)--18.0 grams Acetic acid (glacial)-l2.0 ml.

Potassium alum20.0 grams Water to make1.0 liter pH at 68 F., 4.4-4.7

Samples of the element were also run through an automatic processing machine (Consolidated Eletcrodynarnics Corporation Processor CEC 23-109) containing the above solutions at rates of 8, 12 and 16 feet per minute, all of which produced good clear images having good color discrimination for the magenta and cyan dye traces.

A sample of the element was exposed in a Edgerton, Germeshausen and Grier Mark VI Model sensitometer for microseconds through a 21-step V2 wedge. The sample strip was light-developed for 3 minutes by irradiation from a fluorescent lamp at an intensity of 32 footcandles. An image became visible in 20 seconds. After 3 minutes, 17 steps of the wedge were visible. The image was a deep blue to black trace against a light bufi background. A sample of the material was exposed in the above sensitometer and chemically processed by developing a conventional metol-hydroquinone developer for 15 seconds at 100 F. and yielded after fixing and washing, a 17-step image having a Dmax of 1.0 and 0.01 background density, said image being black.

EXAMPLE II Example I was repeated except that in the outer layer there was added in addition to the magenta color former, a yellow polymeric color former having the formula:

7 Example I. This example showed greater color discrimination between the traces recorded in the upper and lower layers, the magenta-yellow former combination giving a redder color to the oscillographic trace recorded in this layer. This provided good discrimination when compared with the cyan dye trace.

EXAMPLE III A gelatino-silver halide emulsion was prepared by slowly adding an aqueous solution containing a mixture of 1 mole of silver nitrate and 0.033 mole of plumbous nitrate to an aqueous gelatin solution containing 1 mole of potassium chloride and acidified with 0.05 mole of hydrochloric acid. The precipitation was carried out under a red safelight. The temperature at precipitation and for 40 minutes thereafter was held at 160 F. After precipitation, an aqueous solution of 1.6 moles of potassium bromide was added while the mixture was held for 40 min. at 160 F. The resulting emulsion was coagulated, washed and redispersed in the manner described in Example I of Moede, U.S. Patent 2,772,165. To the redispersed emulsion there was added 0.0005 mole percent of sodium aurous thiosulfate based on the silver halide calculated as silver bromide. A green sensitizing oxacarbocyanine dye was added to the emulsion and the latter was digested for 40 minutes at 140 F. After digestion there was added 2.2 mole percent of potassium iodide and 8 mole percent of ammonium thiocyanate. The emulsion was thoroughly stirred.

To a similar emulsion from oxacarbocyanine dye there was added the magenta color former described in Example I. The emulsions were coated, dried and tested in the manner described in Example I to provide oscillographic color trace images having good color discrimination under chemical color development processing and good image quality with low background density under white light trace exposure and photolytic development.

EXAMPLE IV Example I was repeated except that a yellow filter layer was interposed between the magenta color former containing emulsion layer and the cyan color former containing emulsion layer. All other operations were carried out as described in Example I. The image traces resulting from chemical processing showed good color discrimination.

EXAMPLE V Example III was repeated except that the cyan color former had the following formula:

(HI N @CONHU SOaI-I SOzH and the magenta color former had the following formula:

C17H35CCH2 The emulsions were coated, dried and tested in the manner described in Example I to provide oscillographic color trace images having good color discrimination under chemical color development processing and good image quality of low background density under white light trac exposure and photolytic development.

In place of the gelatin binding agent used in the for going examples there can be substituted synthetic waterpermeable organic colloid binding agents. Such agents include water-soluble or permeable polyvinyl alcohol and its derivatives, e.g., partially hydrolyzed polyvinyl acetates, polyvinyl ethers, and acetals containing a large number of intralinear CH CHOH groups, hydrolyzed interpolymers of vinyl acetate and unsaturated addition polymerizable compounds, for example maleic anhydride, acrylic and methacrylic acid esters and styrene. Suitable colloids of the last mentioned type are disclosed in U.S. Patents 2,276,322, 2,276,323, and 2,397,866. The useful polyvinyl acetals include polyvinyl acetaldehyde acetal, polyvinyl butyraldehyde acetal, and polyvinyl sodium 0- sulfobenzaldehyde acetal. Other useful colloid binding agents include the polyvinyl lactams of Bolton, U.S. Patent 2,495,918, e.g., poly-N-vinyl pyrrolidone; the hydrophilic copolymer of N-acrylamido alkyl betaines in Shacklett, U.S. Patent 2,833,650 and hydrophilic cellulose ethers and esters.

Suitable supports for the novel photographic emulsions of this invention include those in the prior art for lightwriting and oscillographic recording. The preferred support is photographic grade paper but may be of any material suitable for coating photographic emulsions such as cellulose ester films and the film base materials disclosed in Alles, et al., U.S. Patent 2,627,088 and Alles, U.S. Patent 2,779,684 and polystyrene. Where paper is used brightening agents of the triazinyl stilbene type compounds may be incorporated either in the emulsions or in the papers.

In place of the polymeric color formers disclosed above, the lipophilic color formers containing high molecular weighting groups disclosed in the above mentioned Chu et al., application Ser. No. 447,573 may also be used. Useful also are the polyvinyl acetal color formers and the color-coupling developing agents disclosed in the following patents: 2,310,903; 2,423,572; 2,476,988; 2,320,- 422; 2,464,597; 2,477,462; 2,380,032; 2,465,067; 2,513,- 189; 2,380,033; 2,472,666; 2,513,190; 2,397,864; 2,472,- 910; 2,538,257; 2,397,865; 2,472,911; 2,562,527; 2,415,- 381; 2,472,913; 2,562,528; 2,422,680; 2,473,403; 2,575.- 182.

The above described photorecording elements invention have many advantages over the prior art. In addition to the advantages demonstrated by the photosensitive elements of the above Sincius applications, this invention provides elements whereby multiple traces each with its distinctive color can be recorded in superposed relation and data shown thereby can be readily distinguished for informational purposes. The elements of this invention are quite versatile insofar as image retrieval is concerned. By being able to be photolyzed or lightdeveloped the black and white images are retrieved in a matter of seconds after exposure and may be used for ready reference or for extended study because of greater stability against image fading and background growth. By being able to color develop the traces to different colors the invention provides a permanent reference in positively identifiable colors.

As will be obvious to those skilled in the art, more than two layers may be used each with a different color former to provide an even wider spectrum of color trace discrimination.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A photorecording element comprising a support bearing in either order (1) a direct-writing, light-developable, blue-sensitive silver halide layer containing a sensitizing dye to provide an extra range of sensitivity in the green and/or red regions of the spectrum, and

of this (2) a direct-writing, light-developable, blue-sensitive silver halide layer free from a sensitizing dye; said layers containing:

(A) a halogen acceptor free from sensitizing dye functions, and

(B) at least one color coupler capable of forming a dye upon color coupling development of a latent silver image with the oxidation products of a primary aromatic amine color developing agent.

2. An element according to claim 1 having a yellow filter layer between layers (1) and (2).

3. An element according to claim 1 wherein said silver halide grains are formed in the presence of a plumbous salt.

4. An element according to claim 1 wherein said silver halide grains are initially formed in the presence of a plumbous salt.

5. An element according to claim 1 wherein said support is paper.

6. An oscillograph photorecording element comprising a support bearing in either order (1) a direct-writing, light-developable, blue-sensitive silver halide layer containing a sensitizing dye to provide an extra range of sensitivity in the green and/ or red regions of the spectrum, and

(2) a direct-writing, light-developable, blue-sensitive silver halide layer free from a sensitizing dye; said layers containing silver halide grains having average grain size in the range 0.1-10.0 microns dispersed in a water-permeable organic macromolecular colloid having protective colloid properties, each of said layers containing, based on the silver halide,

(a) 0.1 to 300 mole percent of cuprous thiocyanate, or (b) 0.5 to 15 mole percent of an iodide ion-yielding compound, and 0.1 to 120 mole percent of a water-soluble thiocyanate salt, and optionally (c) 0 to 120 mole percent of a water-soluble bromide, and

(d) 0 to 25 mole percent of a water-soluble plumbous salt; at least one of said layers containing (e) at least one color former capable of forming a quinoneimine dye upon color-coupling development with the oxidation products of a primary aromatic amine color developing agent.

7. An element according to claim 6 wherein said support is paper.

8. An element according to claim 6 wherein said support is paper, and there is at least one color former in each silver halide layer.

9. An element according to claim 6 wherein the silver halide layer containing the sensitizing dye contains a cyan color former and the other layer contains a magenta color former.

10. An element according to claim 6 wherein the silver halide layer containing the sensitizing dye contains a cyan color former and the other layer contains a magenta color former and a yellow color former.

11. An element according to claim 6 wherein the silver halide grains of said emulsion are formed in the presence of the plumbous salt.

12. An element according to claim 6 wherein the silver halide grains of said emulsion are initially formed in the presence of the plumbous salt.

No references cited.

NORMAN G. T ORCHIN, Primary Examiner J. R. HIGHTOWER, Assistant Examiner US. Cl. X.R. 96-74 

